Lab Midterm Flashcards
(92 cards)
Dendrites
recieve stimuli through ligand-gates or mechanically gated ion channels; in sensory neurons they produce generator or receptor potentials
Cell body
recieves stimuli and produces ESPs or ISPs through activation of ligand-gates ion channels
axon hillock
trigger zone in many neurons; controls initiation of electrical impulses based on input recieved and if input reaches threshold
axon collateral
propagates nerve impulses from initial segment (or from dendrites of sensory neurons) to axon terminals in self-regenerating manner, impulse amplitude does not change as it propagates along an axon.
axon terminal
inflow of Ca+ caused by depolarizing phase of nerve impulse, triggers exocytosis of neurotransmitter from synaptic vesicles
synaptic end bulb
enlarged endings of axon terminals; neurotransmitters are released from here via exocytosis
Schwann cells
form the myelin sheath around axons in the PNS just like oligodendrocytes in the CNS
Myelin sheath
multilayered lipid and protein covering around some axons that insulate them and increases the speed of nerve impulse conduction
Neurolemma
outer nucleated cytoplasmic layer of the schwann cell. Found only in the PNS
Myelin sheath gaps/ nodes of ranvier
gaps in the myelin sheath that appear at intervals along the axon
Gray matter: anterior horn
contain somatic motor neuron nuclei which are clusters of cell bodies of somatic motor neurons that provide nerve impulses for contraction of skeletal muscle
Gray matter: posterior horn
- contain axons of incoming sensory neurons as well as cell bodies and axons of interneurons.
- functions to receive incoming sensory information
White matter
contains major sensory and motor tracts which function as the “highways” along which sensory input travels to the brain and motor output travels from the brain to the skeletal muscle or glands (effectors)
Spinal nerves
paths of communication between the spinal cord and specific regions of the body
Central canal
at the center of the gray commisure; extends the entire length of the spinal cord and is filled with cerebrospinal fluid
Anterior nerve root
the anterior root and rootlets contain axons of motor neurons, which conduct nerve impulses from the CNS to effectors (muscles and glands)
Posterior nerve root
posterior root and rootlets only contain sensory axons which conduct nerve impulses from sensory receptors of the skin, mucles, and internal organs to the CNS
Ganglia
cell bodies of the sensory neurons are located in ganglion
- plays essential role in connecting parts of the peripheral and central nervous systems
Anterior median fissure
- Wide groove on the anterior side
- The spinal pia mater extends into the fissure to line the surfaces of the spinal cord
Posterior median sulcus
- A narrow furrow on the posterior side of the spinal cord
- Not as prominent as anterior median fissure
- divides the spinal cord into halves
Filum terminale
Arising from the conus medullaris is the filum terminale, an extension of the pia mater that extends inferiorly, fuses with the arachnoid mater and dura mater, and anchors the spinal cord the coccyx.
Reflex arc
the route and impulse takes to produce a reflex action
reflex action
the action the body takes when responding the stimulus to help the body maintain homeostasis
Receptor (in reflex)
Dendrites serve as sensory receptors. It responds to a specific stimulus. A change in the internal or external environment produces a graded potential. If the graded potential reaches threshold, it will trigger one or more nerve impulses in a sensory neuron.